Can someone please tell me what this is? It has killed two of my other girls and now seems to be effecting her any help right away would be greatly appreciated. Since there are only three females i moved them to a 5gal, temp is 82' and theres a filter. I really dont want to lose her so i removed the snail and had put in some aq salt because im worried about the other two having whatever it is. Its like a patch of skin was exposed to too much water but in reverse i dont know how to decribe it hope the picture helps

Poor thing......I would get her in high dose aquarium salt 3tsp/gal and tannins along with 100% daily water changes while in QT, get the temp down to 76-77F area and if you can add an airstone this will help too...but you will need at least 1gal QT container so the airstone doesn't stress her too much

Slowly add the salt over an hour start at 1tsp/gal and increase to 3tsp/gal...dissolved first and if you have some tannin from either IAL or dried oak leaf add them too so you can get the water really dark with the tannins-be sure and have the replacement water fussed with the tannins and salt for the water changes to prevent shock...

I feel so bad for the little girl
it looks like shes in pain and barely moves her body the usual way when they swim i have her in treatment as OFL advised so i really really hope i caught her in time. So far she does move very slowly though so i hope to see improvements by morning.